In: Statistics and Probability
Here is a sample data set that appears to be approximately bell-shaped (normal).
40.3 | 38 | 35.1 | 21.4 | 22 | 29.6 |
31.4 | 33.3 | 26 | 15.6 | 33.7 | 48.6 |
29.4 | 46.4 | 37.4 | 11.4 | 38 | 48.6 |
28.6 | 21.7 | 41.8 | 26 | 31.8 | 38.3 |
32.9 | 34.7 | 38.3 | 44 | 35.4 | 46.4 |
35.9 | 31.4 | 23.3 | 24.9 | 14.3 | 35.7 |
26.9 | 27.8 | 44 | 30 | 23.2 | 37 |
28.2 | 27.6 | 44.7 | 34.2 | 48.5 | 25.1 |
25.1 | 31.2 | 16.8 | 18.8 | 26.5 | 35.4 |
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What is the mean of this data set? (Round to two decimal
places)
Mean=Mean=
What is the standard deviation of this data set? (Round to three
decimal places)
SD=SD=
What is the minimum of this data set?
minimum =
How many standard deviations from the mean is minimum in this data
set? (Answer accurate to 3 decimal places. Hint: It is best to use
the unrounded MeanMean and SDSD for this calculation, not the
values reported above.)
Number of SDs =
Is the minimum an unusual value in this data set?
I am using google spreadsheet to analyse the data:
What is the mean of this data set?
mean = 31.900 {using average() function}
What is the standard deviation of this data set?
standard deviation = 9.085 Actual-value = 9.085277329
What is the minimum of this data set?
min = 11.4
How many standard deviations from the mean is minimum in this data set?
To find this, subtract from mean the minimum value and then divide by the standard deviation.
how far the minimum is from the mean in terms of standard deviation :
(31.900 - 11.4) / 9.085277329 = 2.256397824
Ans: 2.256. Therefore, the minimum is 2.256 times the standard deviations away from the mean.
Is the minimum an unusual value in this data set?
Although this value is quite small compared to other values, because of the underlying assumption that the data is approximately normal, there is a 0.12% probability of occurrence of this number. Check this from z-score table.